Expandable pen



FIG. 1 is a front side perspective view of the expandable pen showing my new design;

FIG. 2 is a side elevational view thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a back elevational view thereof;

FIG. 5 is a bottom plan view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a front side perspective view thereof, in an expanded condition with the writing point extended. 

The ornamental design for a expandable pen, as shown and described. 